In a typical optical microscope, light passing through a sample is delivered to the eye of a user, a film, or a sensor through lenses, which then forms an image that is representative of the sample.
In other approaches, light representative of a sample can be detected and used to form an image of the sample without lenses by placing the sample on or near a detector, for example, an integrated circuit, that includes an arrangement of light sensitive elements. Signals generated by the detector can be processed to derive an image.